Cannot add or update a child row: a foreign key constraint fails (`kims`.`questi on`,

66 New Member

Hi sir i want to transform the data of one table into another through foreign key but the following error come to my browser

Cannot add or update a child row: a foreign key constraint fails (`kims`.`questi on`, CONSTRAINT `fk_question_su bject` FOREIGN KEY (`sub_code`) REFERENCES `subject` (`subject_code` ) ON DELETE NO ACTION ON UPDATE NO ACTION)

Here is my code and data base structure.

Expand|Select|Wrap|Line Numbers

 CREATE TABLE IF NOT EXISTS `subject` (

  `subject_code` int(11) NOT NULL AUTO_INCREMENT,

  `Name` text,

  PRIMARY KEY (`subject_code`)

) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=105 ;
 
--

-- Dumping data for table `subject`

--
 
INSERT INTO `subject` (`subject_code`, `Name`) VALUES

(101, 'computer sciense'),

(102, 'Maths'),

(103, 'English'),

(104, 'Chemistry');
 
*********************************************************
 
and the question table is:
 
CREATE TABLE IF NOT EXISTS `question` (

  `question_id` int(11) NOT NULL AUTO_INCREMENT,

  `question` text,

  `weight` int(11) DEFAULT NULL,

  `sub_code` int(11) NOT NULL,

  PRIMARY KEY (`question_id`,`sub_code`),

  KEY `fk_question_subject` (`sub_code`)

) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=205 ;
 
--

-- Dumping data for table `question`

--
 
--

-- Constraints for dumped tables

--
 
--

-- Constraints for table `question`

--

ALTER TABLE `question`

  ADD CONSTRAINT `fk_question_subject` FOREIGN KEY (`sub_code`) REFERENCES `subject` (`subject_code`) ON DELETE NO ACTION ON UPDATE NO ACTION;

Here is my code:

Expand|Select|Wrap|Line Numbers

  
<?php
 
session_start();
 
 include("conn.php");

     connect();

if($_GET['action']=="add")

{
 
//$sub_code=$_POST['sub_code'];

$sub_name=$_POST['sub_name'];
 
$result=mysql_query("insert into subject values('','$sub_name')") or die(mysql_error());
 
/*echo "<script>window.alert('News Added Successfully') </script>";*/

}

?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />

<title>Untitled Document</title>

<link href="KIMS-CSS.css" rel="stylesheet" type="text/css" />

<style type="text/css">

<!--

.style1 {font-size: 14px}

-->

</style>
 
<body>

<?php

$access = $_SESSION["access"];

if ($access != "authorized")

echo "<script>window.alert('You are not allowed to use this page'); window.location.replace('main_login.php'); </script>";
 
?>

<TABLE width="90%" border="0">

  <TR>

    <TD class="blue-17-bold"><DIV align="center" class="table-title-row style1">Add Subject </DIV></TD>

  </TR>

</TABLE>

<p>&nbsp;</p>

<form id="form1" name="form1" method="post" action="add_subject.php?action=add">

  <table width="356" border="1" align="center">
 
    <tr>

      <td>Subject Name</td>

      <td><input name="sub_name" type="text" id="descrip" onchange="return change(this)"/></td>

    </tr>

    <tr>

      <td colspan="2" align="center"><div>

        <label>

        <input name="Submit" type="submit" id="Submit" value="Add Subject" />

        </label>

      </div></td>

    </tr>

  </table>

</form>

<div>

  <div align="center" class="table-title-row style1">Show Subjects </div>

</div>

<p>&nbsp;</p>
 
<table width="716" border="1">

  <tr>

    <td width="105">Subject Code</td>

    <td width="110">Subject Name</td>
 
    <td width="66">Delete</td>

      </tr>

  <?php
 
$select=mysql_query("select * from subject") or die(mysql_error());
 
while($rs=mysql_fetch_array($select))

{

         $var=$rs[subject_code];

          $sub=$rs[Name];

?>

  <tr>

    <td><?php echo $rs['subject_code']; ?></td>

    <td><?php echo "<a href='add_question.php?code=$var&Name=$sub'> $rs[Name]</a><br/>"; ?></td>

    <td><a href="delete_subject.php?id=<?php echo $rs['subject_code']; ?>">Delete</a></td>

  </tr>

  <?php

  }

  ?>

</table>

</body>

</html>

and the add question page code is:

Expand|Select|Wrap|Line Numbers

  
<?php

session_start();

include("conn.php");

     connect();

$sub_code=$_GET['code'];

echo"$sub_code";
 
if($_GET['action']=="add")

{
 
//$sub_code=$_POST['sub_code'];

$question=$_POST['question'];

$weight=$_POST['weight'];
 
$result=mysql_query("insert into question values('','$question','$wieght','sub_code')") or die(mysql_error());
 
//*echo "<script>window.alert('News Added Successfully') </script>";*/

}

?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />

<title>Untitled Document</title>

<link href="KIMS-CSS.css" rel="stylesheet" type="text/css" />

<style type="text/css">

<!--

.style1 {font-size: 14px}

-->

</style>
 
</head>

<body>

<?php

$access = $_SESSION["access"];

if ($access != "authorized")

echo "<script>window.alert('You are not allowed to use this page'); window.location.replace('main_login.php'); </script>";
 
?>

<table width="90%" border="0">

  <tr>

    <td class="blue-17-bold"><div align="center" class="table-title-row style1">Add Question </div></td>

  </tr>

</table>

<p>&nbsp;</p>

<form id="form1" name="form1" method="post" action="add_question.php?action=add">

  <table width="356" border="1" align="center">
 
    <tr>

      <td>Question</td>

      <td><input name="question" type="text" id="descrip" onchange="return change(this)"/></td>

    </tr>

<tr>

      <td>Weight</td>

      <td><input name="weight" type="text" id="descrip" onchange="return change(this)"/></td>

    </tr>

    <tr>

      <td colspan="2" align="center"><div>

        <label>

        <input name="Submit" type="submit" id="Submit" value="Add Subject" />

        </label>

      </div></td>

    </tr>

  </table>

</form>

<div>

  <div align="center" class="table-title-row style1">Show Subjects </div>

</div>

<p>&nbsp;</p>
 
<table width="716" border="1">

  <tr>

    <td width="105">Question Id    </td>

    <td width="110">Question</td>

<td width="110">Wieght</td>

<td width="110">Subject Code</td>
 
    <td width="66">Delete</td>

      </tr>

  <?php
 
$select=mysql_query("select * from question") or die(mysql_error());
 
while($rs=mysql_fetch_array($select))

{

         $var=$rs[question_id];

          $sub=$rs[question];

?>

  <tr>$sub_code=$_GET['code'];

    <td><?php echo $rs['question_id']; ?></td>

    <td><?php echo "<a href='add_answer.php?code=$var&Name=$sub'> $rs[questin]</a><br/>"; ?></td>

<td><?php echo $rs['weight']; ?></td>

<td><?php echo  $rs['sub_code']; ?></td>
 
    <td><a href="delete_subject.php?id=<?php echo $rs['question_id']; ?>">Delete</a></td>

  </tr>

  <?php

  }

  ?>

</table>

</body>

</html>

when i run this the following error occur

Cannot add or update a child row: a foreign key constraint fails (`kims`.`questi on`, CONSTRAINT `fk_question_su bject` FOREIGN KEY (`sub_code`) REFERENCES `subject` (`subject_code` ) ON DELETE NO ACTION ON UPDATE NO ACTION)

plz help thanks in advance....

Sep 28 '10 #1

Subscribe Reply

4914

JKing

1,206

Recognized Expert Top Contributor

You cannot insert data into a child table if the key does not exist in the parent table.

So in your case the related subject must exist before you insert a question for that subject.

Sep 28 '10 #2

semanticnotion

New Member

THANKS jking for your response,
i have already insert the subject before add the related question you can see it my data base table e.g 101 computer science. But the same error occur.

Sep 29 '10 #3

JKing

1,206

Recognized Expert Top Contributor

I think I may have spotted the source of your problem

Expand|Select|Wrap|Line Numbers

 
$result=mysql_query("insert into question values('','$question','$wieght','sub_code')") or die(mysql_error());

There is no $ in front of your sub_code variable so it is trying to insert the value "sub_code" and not the variable.

Sep 29 '10 #4

semanticnotion

New Member

I put $sub_code in query but still it not working. It take one question but when i insert another question it gives the above error.

Expand|Select|Wrap|Line Numbers

 $query="INSERT INTO  `kims`.`question` (`question` ,`weight` ,`sub_code`)VALUES ('$question',  '$weight',  '$sub_code')";
 
 

Sep 30 '10 #5

JKing

1,206

Recognized Expert Top Contributor

I think you need to possibly rework your form and rethink some of your logic here.

If you echo out your query before you run it, I think it will help illustrate your problem. You are rewriting your sub code variable to an empty string when you submit your add question form.

Sep 30 '10 #6

semanticnotion

New Member

yap i echo the query at first it take the value of $sub_code but when i insert another question the $sub_code is empty whats the reason of this i am not sure where i have a mistake.

Oct 4 '10 #7

Similar topics

36261

Cannot add or update a child row: a foreign key constraint fails

by: Ralph Smith | last post by:

I'm having trouble copying a database to another machine. Here are the two table's in ths database and the sql commands: DROP TABLE IF EXISTS `clients`; CREATE TABLE `clients` ( `client_id` int(10) unsigned NOT NULL auto_increment, `lastname` char(15) NOT NULL default '', `firstname` char(15) NOT NULL default '', `birthdate` date NOT NULL default '0000-00-00',

MySQL Database

2893

parent column in child row

by: Frank | last post by:

Hello, I have a dataset with 2 tables and a relation (parent - child). I linked that ds to a datagrid. Shows everything fine (very little coding for such functionality!). But.. in the child row I want to show a column of the parent. Example: orderColumn shows customerId and I want the customerName which is located in the parent. How do I do that? Thanks in advance Frank

Visual Basic .NET

5447

"ERROR 1216: Cannot add or update a child row" but parent record exists

by: fuimens | last post by:

Hi, With mysql-4.0.20, I have a problem inserting data with foreign key references, MySQL saying ERROR 1216: Cannot add or update a child row: a foreign key constraint fails The message is confusing because a parent record in parent table exists !? The "show innodb status; " command prints :

MySQL Database

1195

Bug update child row with two datagrid

by: Zorglub | last post by:

Hi, I have a windos form with two datagrids Master and Detail, I use a dataset with two datatable and a relation between Table1 and Table2. I set the datagrid like : DataViewManager dsView = myDataSet.DefaultViewManager; dataGrid1.DataSource = dsView; dataGrid1.DataMember = "NAMEFIRSTTABLE"; dataGrid2.DataSource = dsView; dataGrid2.DataMember = "NAMERELATION";

C# / C Sharp

6831

How update one row with timestamp diferent

by: Ivan | last post by:

Thanks to answer topic previous!!!! I use this script to update one table MERGE INTO EIS.CLI_HISTORY TXN USING EIS.CLI_MAPING CLI ON TXN.CLIENTID = CLI.CLIENTID WHEN MATCHED AND CLI.STATUSID = 3 AND CLI.CLIENTID != CLI.MAPPEDCLIENTID AND

DB2 Database

9850

Mysql Using Navicat (error --- Foreign Key Fails)

by: Harshpandya | last post by:

Hi I am new at ASP and MYSQL. I am Using Navicat to access MYSQL database. My Problem is when i create the foreign key in "Navicat" -it gives me this error. 1452-cannot add or update child row: a foreign key constraint fails.... Can any body help me - why am i getting this error - and how to fix it --

MySQL Database

5969

cannot add or update a child row

by: nitinkhare1 | last post by:

Please help,I'm very frustated. when I ADD the data in kn_history_question table of htbase_tst database....it giving the error "Cannot add or update a child row:a foreign key constraint fails,<'htbase_tst/kn_history_question', CONSTRAINT 'FK_kn_history_question_complaint' FOREIGN KEY ('complaint_id' ) REFERENCES 'complaint'('id')). This is my table script..... CREATE TABLE `city` ( `id` int(11) NOT NULL auto_increment, ...

MySQL Database

13301

Cannot update ODBC linked table even though I have R/W access to the table

by: nzaiser | last post by:

Hello! This is my first time asking a question here, so please bear with me if I seem 'unconventional!' My issue is this..... OS: Windows_NT App: MS Access 2000 (also in 2003) ODBC linked table into a DB for which I have read/write/delete authority. I have verified the authority in the source DB - ad nauseum - it works. Tested the table in question (Region) specifically and another table (Store_Info) as well. I can open the Region...

Microsoft Access / VBA

2662

Dataset.GetXml() returns "A child row has multiple parents" exception

by: muaddubby | last post by:

Hi I've got a situation with a dataset that contains two tables with a many-to-one relationship, and am trying to extract the data in xml format. When I execute the GetXml() method, and exception is thrown telling me that "A child row has multiple parents", and the xml is obviously not generated. The output I'm expecting is something like this: <parent> <parentRecnum>1</parentRecnum> <childRecnum>1</childRecnum> <child>

.NET Framework

9563

What is ONU?

by: marktang | last post by:

ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...

General

9386

Changing the language in Windows 10

by: Hystou | last post by:

Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...

Windows Server

10145

Problem With Comparison Operator <=> in G++

by: Oralloy | last post by:

Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...

C / C++

9998

Maximizing Business Potential: The Nexus of Website Design and Digital Marketing

by: jinu1996 | last post by:

In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...

Online Marketing

9938

The easy way to turn off automatic updates for Windows 10/11

by: Hystou | last post by:

Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...

Windows Server

8822

AI Job Threat for Devs

by: agi2029 | last post by:

Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...

Career Advice

6642

Couldn’t get equations in html when convert word .docx file to html file in C#.

by: conductexam | last post by:

I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...

C# / C Sharp

3917

transfer the data from one system to another through ip address

by: 6302768590 | last post by:

Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system

C# / C Sharp

3523

How to add payments to a PHP MySQL app.

by: muto222 | last post by:

How can i add a mobile payment intergratation into php mysql website.

PHP